1. Field of the Invention
The present invention relates to a rotor for a rotary electric machine such as an electric motor or a generator, etc., mounted to an automotive vehicle such as an automobile, etc., or a marine vessel, etc., and particularly to a rotor core construction.
2. Description of the Related Art
Conventional rotor cores for rotary electric machines are constructed by laminating a plurality of steel plates relative to an axis of rotation, apertures for separating a field coil insertion portion and magnetic poles being disposed on each of the steel plates, and an outer peripheral surface thereof being formed so as to be smooth by disposing a thin layer portion so as to cover the apertures to suppress the occurrence of wind-splitting noise. (See Patent Literature 1, for example.)
Patent Literature 1: Japanese Patent Laid-Open No. 2002-247817 (Gazette: Claims)
However, in conventional rotors for rotary electric machines, because the rotor core is constructed by laminating steel plates, the strength of the magnetic poles themselves is reduced. Thus, the magnetic poles may disintegrate during high-speed rotation of the rotor, or stresses may occur in a magnetic pole portion during an assembly process in which a rotating shaft is pressed into the rotor core, deforming the magnetic poles themselves, etc. This deformation of the magnetic poles themselves brings about deterioration in dimensional precision, leading to increased irregularities in output from the rotor.
Furthermore, layers of air form easily between the laminated steel plates. When layers of air form between the laminated steel plates, magnetic resistance is increased, making output deteriorate.